Fabrication of full coverage restorations for existing removable partial dentures

Fabrication removable

of full coverage restorations partial dentures

D. Ray McArthur,

for existing

D.D.S., M.S.*

University of North Carolina,

School of Dentistry, Chapel Hill, N.C.

0

n occasion full coverage restorations must be fabricated for abutments to existing removable partial dentures. Several techniques are available. The choice is often influenced by the ability of the patient to be without the removable partial denture while the fixed unit is fabricated. One approach is the direct fabrication of a grosspattern with autocuring acrylic resinsso that the patient can continue to wear the restoration. However, the insertion of the new casting (full cast or porcelain fused to metal) and the subsequentfit of the involved removable partial denture may occasionallybe lessthan ideal. The sourceof the problem seemsto be related to inadequate fit of the grossresin pattern on the working die. In the technique describedherein, the patient must be without the involved denture during fabrication of the cast restoration. However, the final result may outweigh the inconvenience.

2. Select a full arch impressiontray that will fit the remaining teeth as well as the removable partial denture. 3. Place a small amount of impression material around the abutment tooth with the technique of your choice. Seat the removable partial denture. 4. Seat the loaded impresh;iontray over the natural teeth and the denture. It is critical that the removable

METHODS Clinical procedures 1. Prepare the involved abutment tooth for full coverage restoration. *As&ate

Professor,

Removable

Prosthodontk

Fig. 1. Full arch rubber base impression that contains involved removable partial denture and records prepared tooth and remaining natural teeth. 574

Fig. 2. Working cast with existing partial denture.

Fig. 3. Mounted trimmed die.

working

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1984

prepared

cast

tooth

with

VOLUME

related

ditched

S-l

NUMBER

to

or

4

FULL

COVERAGE

RESTORATIONS

Fig. 4. A, Buccal view of wax-up for porcelain-fusedto-m Etc

.etal abutment crown. B, Occlusal view of crown -up. Note wax adaptation to occlusal rest and :a1clearance for porcelain application.

Fig. 5. Abutment on working cast.

casting and partial denture seated

partial denture remain properly seated during this portion of the procedure. 5. Remove the tray with the cured impression. The involved denture will usually be removed with the impression tray. If not, reseat the removable partial denture into the impression (Fig. 1). THE

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OF PROSTHETIC

DENTISTRY

Fig. 6. Views of surveyed and contoured porcelain with seated partial denture. Note survey line and clasp adapstation to porcelain.

Fig. 7. Stained and glazed crown cemented in place after its relationship to partial denture and adjacent and opposing teeth has been verified.

Laboratory

procedures

1. Pour the impression of the tooth preparation in die stone. 2. Block out undercuts in the acrylic resin denture base extensions. Pour the remainder of the impression and acrylic resin extensions in dental stone. 575

McARTHUR

6. Cast the pattern and return it to the working die (Fig. 5). 7. Apply porcelain if the restoration is porcelain fused to metal. The final facial contour is completedby use of the dental surveyor and the existing retentive clasp as a guide (Fig. 6).

Clinical

procedure

If care has been taken, the clinical insertion and adjustment should be no more than the insertion of routine full coverage restorations (Figs. 7 and 8).

SUMMARY

Fig.

8. Relationship

of existing

removable

partial

denture to abutment crown. 3. When set, separatethe cast from the impression. Removethe denture from the cast. Trim the margins of the die. Return the removable partial denture to the working cast (Fig. 2). 4. Mount the castwith the seateddenture to the cast of the opposing arch (Fig. 3). 5. Wax the crown contour to be compatible with the direct retainer (Fig. 4).

A technique hasbeendescribedfor the fabrication of full coveragerestorationsfor existing removable partial dentures. This method requires that the patient be deprived of the removable prosthesisduring the fabrication of the fixed replacement unit. Clearly, this may not always be possibleor desirable;however, when it is possible,the end result outweighs the inconvenienceto the patient.

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to subpctibers

Bound volumesof the JOURNALOF PROSTHETIC DENTISTRY areavailableto subscribers (only) for the 1984 isews from the publisher at a cost of $39.99 ($49.09 international) for Vol. 51 (January-June) and Vol. 52 (July-December). Shipping charges are included. Each bound volume contains a subject and author index, and ah advertising is removed. Copiesare shipped within 30 days after publication of the last isaue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. ContactThe C. V. Mosby Co., Circulation Department, 11830 Westline Industrial Drive, St. Louis, MO 63146, USA; phone (309) 325-4177, ext. 351. Subscriptions must subscription.

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in force

to qualify.

Bound

volumes

are

not

available

in place

of

a regular

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576

APRIL

1984

VOLUME

51

NUMBER

4